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Baronio D, Chen YC, Panula P. Abnormal brain development of monoamine oxidase mutant zebrafish and impaired social interaction of heterozygous fish. Dis Model Mech 2021; 15:273667. [PMID: 34881779 PMCID: PMC8891935 DOI: 10.1242/dmm.049133] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 12/01/2021] [Indexed: 11/20/2022] Open
Abstract
Monoamine oxidase (MAO) deficiency and imbalanced levels of brain monoamines have been associated with developmental delay, neuropsychiatric disorders and aggressive behavior. Animal models are valuable tools to gain mechanistic insight into outcomes associated with MAO deficiency. Here, we report a novel genetic model to study the effects of mao loss of function in zebrafish. Quantitative PCR, in situ hybridization and immunocytochemistry were used to study neurotransmitter systems and expression of relevant genes for brain development in zebrafish mao mutants. Larval and adult fish behavior was evaluated through different tests. Stronger serotonin immunoreactivity was detected in mao+/− and mao−/− larvae compared with their mao+/+ siblings. mao−/− larvae were hypoactive, and presented decreased reactions to visual and acoustic stimuli. They also had impaired histaminergic and dopaminergic systems, abnormal expression of developmental markers and died within 20 days post-fertilization. mao+/− fish were viable, grew until adulthood, and demonstrated anxiety-like behavior and impaired social interactions compared with adult mao+/+ siblings. Our results indicate that mao−/− and mao+/− mutants could be promising tools to study the roles of MAO in brain development and behavior. This article has an associated First Person interview with the first author of the paper. Summary: We assessed developmental, neurochemical and behavioral alterations displayed by mao+/− and mao−/− zebrafish, establishing that these model organisms are promising tools to study the consequences of MAOA/B deficiency.
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Affiliation(s)
- Diego Baronio
- Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - Yu-Chia Chen
- Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - Pertti Panula
- Department of Anatomy, University of Helsinki, Helsinki, Finland
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2
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Wegener Sleeswijk A, Heijungs R, Durston S. Tackling Missing Heritability by Use of an Optimum Curve: A Systematic Review and Meta-Analysis. Int J Mol Sci 2019; 20:ijms20205104. [PMID: 31618836 PMCID: PMC6829377 DOI: 10.3390/ijms20205104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/07/2019] [Accepted: 10/12/2019] [Indexed: 11/28/2022] Open
Abstract
Missing heritability is a common problem in psychiatry that impedes precision medicine approaches to autism and other heritable complex disorders. This proof-of-concept study uses a systematic review and meta-analysis of the association between variants of the serotonin transporter promoter (5-HTTLPR) and autism to explore the hypothesis that some missing heritability can be explained using an optimum curve. A systematic literature search was performed to identify transmission disequilibrium tests on the short/long (S/L) 5-HTTLPR polymorphism in relation to autism. We analysed five American, seven European, four Asian and two American/European samples. We found no transmission preference in the joint samples and in Europe, preferential transmission of S in America and preferential transmission of L in Asia. Heritability will be underestimated or missed in genetic association studies if two alternative genetic variants are associated with the same disorder in different subsets of a sample. An optimum curve, relating a multifactorial biological variable that incorporates genes and environment to a score for a human trait, such as social competence, can explain this. We suggest that variants of functionally related genes will sometimes appear in fixed combinations at both sides of an optimum curve and propose that future association studies should account for such combinations.
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Affiliation(s)
- Anneke Wegener Sleeswijk
- Department of Psychiatry, University Medical Center Utrecht Brain Center, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
| | - Reinout Heijungs
- Department of Econometrics and Operations Research, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands.
- Institute of Environmental Sciences, Department of Industrial Ecology, Leiden University, Einsteinweg 2, 2333 CC Leiden, The Netherlands.
| | - Sarah Durston
- Department of Psychiatry, University Medical Center Utrecht Brain Center, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
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Yang PY, Menga YJ, Li T, Huang Y. Associations of endocrine stress-related gene polymorphisms with risk of autism spectrum disorders: Evidence from an integrated meta-analysis. Autism Res 2017; 10:1722-1736. [PMID: 28656683 DOI: 10.1002/aur.1822] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/12/2017] [Accepted: 05/23/2017] [Indexed: 02/05/2023]
Abstract
Autism spectrum disorders (ASD) are related to serotonin transporter (5-HTT) and catechol-O-methyl transferase (COMT) as two most monoaminergic polymorphic variations. However, multiple studies assessing rs4680 and 5-HTTLPR variants in ASD have reported inconsistent results. Therefore, we conducted an integrated meta-analysis to combine case-control and transmission/disequilibrium test (TDT) studies to determine whether COMT and 5-HTT are associated with ASD. We searched multiple electronic databases (PubMed, EmBase and Web of Science) to identify studies assessing the rs4680 and 5-HTTLPR variants in ASD from Jan 1997 to Dec 2016. Then allelic data from case-control and TDT studies were analyzed by the Catmap package in the R software. A total of 5 studies were eligible for the meta-analysis of rs4680, including 3 case-control, 1 TDT and 1 TDT & case-control studies. Meanwhile, 22 studies of 5-HTTLPR were available, including 16 TDT, 4 case-control and 2 TDT & case-control studies. The current meta-analysis included 814 ASD cases, 741 controls and 311 families related to rs4680; 749 ASD cases, 1,118 controls and 1,861 families relevant to 5-HTTLPR were also evaluated. For rs4680, the pooled OR was 1.18 (95% CI = 0.87-1.59, P = 0.29, Pheterogeneity < 0.00001). There was no significant association of rs4680 with risk of ASD between the two subgroups. For 5-HTTLPR, the pooled OR was 1.05 (95% CI = 0.92-1.20, P = 0.4652, Pheterogeneity < 0.00001). Meanwhile, we found no significant risk in individual case-control or TDT studies. The above findings indicated that neither COMT rs4680 nor 5-HTT 5-HTTLPR polymorphism significantly affects ASD risk. Autism Res 2017, 10: 1722-1736. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY Our results showed no evidence of significant association of either COMT rs4680 or 5-HTT 5-HTTLPR variants with ASD, showing that these two genes may not be major susceptible genetic factors in ASD occurrence, and may have a reciprocal action with each other in combination with environmental factors. These findings further provide evidence that a single gene variant may not dictate autism occurrence, but possibly contributes to a specific phenotype or subtype of ASD.
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Affiliation(s)
- Ping-Yuan Yang
- Mental Health Center, West China Hospital of Sichuan University, Chengdu, China
| | - Ya-Jing Menga
- Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Tao Li
- Mental Health Center, West China Hospital of Sichuan University, Chengdu, China.,Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Yi Huang
- Mental Health Center, West China Hospital of Sichuan University, Chengdu, China.,Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
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4
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Network Approach to Autistic Traits: Group and Subgroup Analyses of ADOS Item Scores. J Autism Dev Disord 2015. [DOI: 10.1007/s10803-015-2537-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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5
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Jaiswal P, Mohanakumar KP, Rajamma U. Serotonin mediated immunoregulation and neural functions: Complicity in the aetiology of autism spectrum disorders. Neurosci Biobehav Rev 2015; 55:413-31. [PMID: 26021727 DOI: 10.1016/j.neubiorev.2015.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 12/19/2022]
Abstract
Serotonergic system has long been implicated in the aetiology of autism spectrum disorders (ASD), since platelet hyperserotonemia is consistently observed in a subset of autistic patients, who respond well to selective serotonin reuptake inhibitors. Apart from being a neurotransmitter, serotonin functions as a neurotrophic factor directing brain development and as an immunoregulator modulating immune responses. Serotonin transporter (SERT) regulates serotonin level in lymphoid tissues to ensure its proper functioning in innate and adaptive responses. Immunological molecules such as cytokines in turn regulate the transcription and activity of SERT. Dysregulation of serotonergic system could trigger signalling cascades that affect normal neural-immune interactions culminating in neurodevelopmental and neural connectivity defects precipitating behavioural abnormalities, or the disease phenotypes. Therefore, we suggest that a better understanding of the cross talk between serotonergic genes, immune systems and serotonergic neurotransmission will open wider avenues to develop pharmacological leads for addressing the core ASD behavioural deficits.
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Affiliation(s)
- Preeti Jaiswal
- Manovikas Biomedical Research and Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata 700 107, India
| | - Kochupurackal P Mohanakumar
- Division of Cell Biology & Physiology, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata 700 032, India
| | - Usha Rajamma
- Manovikas Biomedical Research and Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata 700 107, India.
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6
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Jaiswal P, Guhathakurta S, Singh AS, Verma D, Pandey M, Varghese M, Sinha S, Ghosh S, Mohanakumar KP, Rajamma U. SLC6A4 markers modulate platelet 5-HT level and specific behaviors of autism: a study from an Indian population. Prog Neuropsychopharmacol Biol Psychiatry 2015; 56:196-206. [PMID: 25261775 DOI: 10.1016/j.pnpbp.2014.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 10/24/2022]
Abstract
Presence of platelet hyperserotonemia and effective amelioration of behavioral dysfunctions by selective serotonin reuptake inhibitors (SSRI) in autism spectrum disorders (ASD) indicate that irregularities in serotonin (5-HT) reuptake and its homeostasis could be the basis of behavioral impairments in ASD patients. SLC6A4, the gene encoding serotonin transporter (SERT) is considered as a potential susceptibility gene for ASD, since it is a quantitative trait locus for blood 5-HT levels. Three functional polymorphisms, 5-HTTLPR, STin2 and 3'UTR-SNP of SLC6A4 are extensively studied for possible association with the disorder, with inconclusive outcome. In the present study, we investigated association of these polymorphisms with platelet 5-HT content and symptoms severity as revealed by childhood autism rating scale in ASD children from an Indian population. Higher 5-HT level observed in ASD was highly significant in children with heterozygous and homozygous genotypes comprising of minor alleles of the markers. Quantitative transmission disequilibrium test demonstrated significant genetic effect of STin2 allele as well as STin2/3'UTR-SNP and 5-HTTLPR/3'UTR-SNP haplotypes on 5-HT levels, but no direct association with overall CARS score and ASD phenotype. Significant genetic effect of the markers on specific behavioral phenotypes was observed for various sub-phenotypes of CARS in quantitative trait analysis. Even though the 5-HT level was not associated with severity of behavioral CARS score, a significant negative relationship was observed for 5-HT levels and level and consistency of intellectual response and general impression in ASD children. Population-based study revealed higher distribution of the haplotype 10/G of STin2/3'UTR-SNP in male controls, suggesting protective effect of this haplotype in male cases. Overall results of the study suggest that SLC6A4 markers have specific genetic effect on individual ASD behavioral attributes, might be through the modulation of 5-HT content.
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Affiliation(s)
- Preeti Jaiswal
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Subhrangshu Guhathakurta
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Asem Surindro Singh
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Deepak Verma
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Mritunjay Pandey
- Lab of Clinical & Experimental Neurosciences, Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Jadavpur, Kolkata, India
| | - Merina Varghese
- Lab of Clinical & Experimental Neurosciences, Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Jadavpur, Kolkata, India
| | - Swagata Sinha
- Out-Patients Department, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India
| | - Saurabh Ghosh
- Human Genetics Unit, Indian Statistical Institute, 203 BT Road, Kolkata, India
| | - Kochupurackal P Mohanakumar
- Lab of Clinical & Experimental Neurosciences, Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Jadavpur, Kolkata, India
| | - Usha Rajamma
- Manovikas Biomedical Research & Diagnostic Centre, Manovikas Kendra, 482 Madudah, Plot I-24, Sector-J, EM Bypass, Kolkata, India.
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7
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Ye W, Xie L, Li C, Nathanielsz PW, Thompson BJ. Impaired development of fetal serotonergic neurons in intrauterine growth restricted baboons. J Med Primatol 2014; 43:284-287. [PMID: 25431504 DOI: 10.1111/jmp.12116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We studied development of the fetal serotonergic central nervous system in a baboon, non-human primate model of intrauterine growth restriction (IUGR). Fetal (90% of full-term) IUGR brains were comparable in size to controls, but have reduced expression of serotonergic proteins and mRNAs, as well as having fewer serotonergic neurons.
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Affiliation(s)
- Wenrui Ye
- Department of Physiology, and Pharmacology. University of Texas Health Science Center, San Antonio, TX 78229-3900
| | - Lynn Xie
- Department of OBGYN and Center for Pregnancy and Newborn Research, and Pharmacology. University of Texas Health Science Center, San Antonio, TX 78229-3900
| | - Cun Li
- Department of OBGYN and Center for Pregnancy and Newborn Research, and Pharmacology. University of Texas Health Science Center, San Antonio, TX 78229-3900
| | - Peter W Nathanielsz
- Department of OBGYN and Center for Pregnancy and Newborn Research, and Pharmacology. University of Texas Health Science Center, San Antonio, TX 78229-3900
| | - Brent J Thompson
- Department of Cellular & Structural Biology, and Pharmacology. University of Texas Health Science Center, San Antonio, TX 78229-3900
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8
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Shastry BS. Recent Advances in the Genetics of Autism Spectrum Disorders: A Minireview. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/096979505799103704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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9
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How to Use the ADI-R for Classifying Autism Spectrum Disorders? Psychometric Properties of Criteria from the Literature in 1,204 Dutch Children. J Autism Dev Disord 2013; 43:2280-94. [DOI: 10.1007/s10803-013-1783-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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10
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Gadow KD, DeVincent CJ, Siegal VI, Olvet DM, Kibria S, Kirsch SF, Hatchwell E. Allele-specific associations of 5-HTTLPR/rs25531 with ADHD and autism spectrum disorder. Prog Neuropsychopharmacol Biol Psychiatry 2013; 40:292-7. [PMID: 23123360 PMCID: PMC3522768 DOI: 10.1016/j.pnpbp.2012.10.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/15/2012] [Accepted: 10/23/2012] [Indexed: 12/16/2022]
Abstract
BACKGROUND The aims of the present study were to examine the association between a common serotonin transporter gene (SLC6A4) polymorphism 5-HTTLPR/rs25531 with severity of attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) symptoms. METHODS Mothers and teachers completed a validated DSM-IV-referenced rating scale for ADHD and ASD symptoms in 118 children with ASD. RESULTS Analyses indicated that children with at least one copy of the S or L(G) allele obtained significantly more severe maternal ratings of hyperactivity (p=0.001; ηp(2)=0.097) and impulsivity (p=0.027; ηp(2)=0.044) but not inattention (p=0.061; ηp(2)=0.032), controlling for ASD severity, than children homozygous for the L(A) allele. Conversely, mothers' ratings indicated that children with L(A)/L(A) genotype had more severe ASD social deficits than S or L(G) allele carriers (p=0.003; ηp(2)=0.081), controlling for ADHD symptom severity. Teachers' ratings though consistent with mothers' ratings of hyperactivity and social deficits were marginally significant (p=0.07/p=0.09). There was some evidence that the magnitude of parent-teacher agreement regarding symptom severity varied as a function of the child's genotype. CONCLUSION The 5-HTTLPR/rs25531 polymorphism or its correlates may modulate severity of ADHD and ASD symptoms in children with ASD, but in different ways. These tentative, hypothesis-generating findings require replication with larger independent samples.
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Affiliation(s)
- Kenneth D. Gadow
- Department of Psychiatry and Behavioral Sciences, Stony Brook University, Stony Brook, NY 11794-8790, Phone: (631) 632-8858, FAX: (631) 632-8953,
| | - Carla J. DeVincent
- Department of Radiology, Stony Brook Medicine, Stony Brook, NY 11794-8460, Phone: (631) 638-2136,
| | - Victoria I. Siegal
- Department of Pathology, Stony Brook University, Stony Brook, NY 11794-8088,
| | - Doreen M. Olvet
- Molecular Imaging and Neuropathology Division (MIND), New York State Psychiatric Institute, Columbia University, 1051 Riverside Drive, Unit 42, New York, NY 10032, USA, Hillside Hospital
| | - Saniya Kibria
- School of Medicine, Stony Brook University, Stony Brook, NY 11794-8088,
| | - Sarah F. Kirsch
- School of Medicine, Stony Brook University, Stony Brook, NY 11794-8088,
| | - Eli Hatchwell
- Department of Pathology, Stony Brook University, Stony Brook, NY 11794-8088,
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11
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Doyle CA, McDougle CJ. Pharmacotherapy to control behavioral symptoms in children with autism. Expert Opin Pharmacother 2012; 13:1615-29. [DOI: 10.1517/14656566.2012.674110] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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12
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Wang L, Angley MT, Gerber JP, Sorich MJ. A review of candidate urinary biomarkers for autism spectrum disorder. Biomarkers 2012; 16:537-52. [PMID: 22022826 DOI: 10.3109/1354750x.2011.598564] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
CONTEXT Autism is a complex, heterogeneous neurodevelopmental condition with a strong genetic component potentially impacted by various environmental factors influencing susceptibility. There are no reliable laboratory tests available to confirm an autism diagnosis. OBJECTIVE To examine the published literature and identify putative urinary biomarkers of autism. METHODS A comprehensive literature search was conducted using electronic bibliographic databases. RESULTS Putative autism biomarkers were identified that could be categorized according to the key theories that exist regarding the etiology of autism: gastrointestinal factors, immune dysregulation, heavy metal toxicity, neurotransmitter abnormalities, and oxidative stress. CONCLUSION There is scope for specific urinary biomarkers to be useful for identification of autistic metabolic phenotypes.
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Affiliation(s)
- Lv Wang
- Sansom Institute for Health Research, University of South Australia, Adelaide
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13
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Glutamate transporter gene (SLC1A1) single nucleotide polymorphism (rs301430) and repetitive behaviors and anxiety in children with autism spectrum disorder. J Autism Dev Disord 2010; 40:1139-45. [PMID: 20155310 DOI: 10.1007/s10803-010-0961-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Investigated association of single nucleotide polymorphism (SNP) rs301430 in glutamate transporter gene (SLC1A1) with severity of repetitive behaviors (obsessive-compulsive behaviors, tics) and anxiety in children with autism spectrum disorder (ASD). Mothers and/or teachers completed a validated DSM-IV-referenced rating scale for 67 children with autism spectrum disorder. Although analyses were not significant for repetitive behaviors, youths homozygous for the high expressing C allele had more severe anxiety than carriers of the T allele. Allelic variation in SLC1A1 may be a biomarker for or modifier of anxiety symptom severity in children with ASD, but study findings are best conceptualized as tentative pending replication with larger independent samples.
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Holt R, Barnby G, Maestrini E, Bacchelli E, Brocklebank D, Sousa I, Mulder EJ, Kantojärvi K, Järvelä I, Klauck SM, Poustka F, Bailey AJ, Monaco AP. Linkage and candidate gene studies of autism spectrum disorders in European populations. Eur J Hum Genet 2010; 18:1013-9. [PMID: 20442744 PMCID: PMC2987412 DOI: 10.1038/ejhg.2010.69] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 04/07/2010] [Accepted: 04/08/2010] [Indexed: 02/05/2023] Open
Abstract
Over the past decade, research on the genetic variants underlying susceptibility to autism and autism spectrum disorders (ASDs) has focused on linkage and candidate gene studies. This research has implicated various chromosomal loci and genes. Candidate gene studies have proven to be particularly intractable, with many studies failing to replicate previously reported associations. In this paper, we investigate previously implicated genomic regions for a role in ASD susceptibility, using four cohorts of European ancestry. Initially, a 384 SNP Illumina GoldenGate array was used to examine linkage at six previously implicated loci. We identify linkage approaching genome-wide suggestive levels on chromosome 2 (rs2885116, MLOD=1.89). Association analysis showed significant associations in MKL2 with ASD (rs756472, P=4.31 x 10(-5)) and between SND1 and strict autism (rs1881084, P=7.76 x 10(-5)) in the Finnish and Northern Dutch populations, respectively. Subsequently, we used a second 384 SNP Illumina GoldenGate array to examine the association in seven candidate genes, and evidence for association was found in RELN (rs362780, P=0.00165). Further increasing the sample size strengthened the association with RELN (rs362780, P=0.001) and produced a second significant result in GRIK2 (rs2518261, P=0.008). Our results strengthen the case for a more detailed study of the role of RELN and GRIK2 in autism susceptibility, as well as identifying two new potential candidate genes, MKL2 and SND1.
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Affiliation(s)
- Richard Holt
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Gabrielle Barnby
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Elena Maestrini
- Dipartimento di Biologia, Università di Bologna, Bologna, Italy
| | - Elena Bacchelli
- Dipartimento di Biologia, Università di Bologna, Bologna, Italy
| | - Denise Brocklebank
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Inês Sousa
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Erik J Mulder
- Department of Psychiatry, Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, The Netherlands
| | - Katri Kantojärvi
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | - Irma Järvelä
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | - Sabine M Klauck
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Fritz Poustka
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany
| | - Anthony J Bailey
- University Department of Psychiatry, Park Hospital for Children, Oxford, UK
| | - Anthony P Monaco
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - the EU Autism MOLGEN Consortium8
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
- Dipartimento di Biologia, Università di Bologna, Bologna, Italy
- Department of Psychiatry, Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, The Netherlands
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany
- University Department of Psychiatry, Park Hospital for Children, Oxford, UK
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15
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Wink LK, Plawecki MH, Erickson CA, Stigler KA, McDougle CJ. Emerging drugs for the treatment of symptoms associated with autism spectrum disorders. Expert Opin Emerg Drugs 2010; 15:481-94. [PMID: 20470188 PMCID: PMC2923687 DOI: 10.1517/14728214.2010.487860] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Autism spectrum disorders, or pervasive developmental disorders (PDDs), are neurodevelopmental disorders defined by qualitative impairment in social interaction, impaired communication and stereotyped patterns of behavior. The most common forms of PDD are autistic disorder (autism), Asperger's disorder and PDD not otherwise specified. Recent surveillance studies reveal an increase in the prevalence of autism and related PDDs. The use of pharmacologic agents in the treatment of these disorders can reduce the impact of interfering symptoms, providing relief for affected individuals and their families. AREAS COVERED IN THIS REVIEW This review examines results from neurobiologic research in an attempt to both elucidate the pathophysiology of autism and guide the development of pharmacologic agents for the treatment of associated symptoms. The safety and efficacy data of drugs currently in clinical use for the treatment of these symptoms, as well as pharmaceuticals currently under development, are discussed. WHAT THE READER WILL GAIN This comprehensive review will deepen the reader's current understanding of the research guiding the pharmacologic treatment of symptoms associated with autism and related PDDs. Areas of focus for future research are also discussed. The need for large-scale investigation of some commonly used pharmacologic agents, in addition to the development of drugs with improved efficacy and safety profiles, is made evident. TAKE HOME MESSAGE Despite progress in the development of pharmacologic treatments for a number of interfering symptom domains associated with autism and other PDDs, a great deal of work remains.
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Affiliation(s)
- Logan K Wink
- Indiana University School of Medicine, Department of Psychiatry, Indianapolis, IN 46202, USA
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Sousa I, Clark TG, Holt R, Pagnamenta AT, Mulder EJ, Minderaa RB, Bailey AJ, Battaglia A, Klauck SM, Poustka F, Monaco AP. Polymorphisms in leucine-rich repeat genes are associated with autism spectrum disorder susceptibility in populations of European ancestry. Mol Autism 2010; 1:7. [PMID: 20678249 PMCID: PMC2913944 DOI: 10.1186/2040-2392-1-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 03/25/2010] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Autism spectrum disorders (ASDs) are a group of highly heritable neurodevelopmental disorders which are characteristically comprised of impairments in social interaction, communication and restricted interests/behaviours. Several cell adhesion transmembrane leucine-rich repeat (LRR) proteins are highly expressed in the nervous system and are thought to be key regulators of its development. Here we present an association study analysing the roles of four promising candidate genes - LRRTM1 (2p), LRRTM3 (10q), LRRN1 (3p) and LRRN3 (7q) - in order to identify common genetic risk factors underlying ASDs. METHODS In order to gain a better understanding of how the genetic variation within these four gene regions may influence susceptibility to ASDs, a family-based association study was undertaken in 661 families of European ancestry selected from four different ASD cohorts. In addition, a case-control study was undertaken across the four LRR genes, using logistic regression in probands with ASD of each population against 295 ECACC controls. RESULTS Significant results were found for LRRN3 and LRRTM3 (P < 0.005), using both single locus and haplotype approaches. These results were further supported by a case-control analysis, which also highlighted additional SNPs in LRRTM3. CONCLUSIONS Overall, our findings implicate the neuronal leucine-rich genes LRRN3 and LRRTM3 in ASD susceptibility.
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Affiliation(s)
- Inês Sousa
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
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17
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Campbell DB, Warren D, Sutcliffe JS, Lee EB, Levitt P. Association of MET with social and communication phenotypes in individuals with autism spectrum disorder. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:438-446. [PMID: 19548256 PMCID: PMC7076810 DOI: 10.1002/ajmg.b.30998] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Autism is a complex neurodevelopmental disorder diagnosed by impairments in social interaction, communication, and behavioral flexibility. Autism is highly heritable, but it is not known whether a genetic risk factor contributes to all three core domains of the disorder or autism results from the confluence of multiple genetic risk factors for each domain. We and others reported previously association of variants in the gene encoding the MET receptor tyrosine kinase in five independent samples. We further described enriched association of the MET promoter variant rs1858830 C allele in families with co-occurring autism and gastrointestinal conditions. To test the contribution of this functional MET promoter variant to the domains of autism, we analyzed its association with quantitative scores derived from three instruments used to diagnose and describe autism phenotypes: the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS), and both the parent and the teacher report forms of the Social Responsiveness Scale (SRS). In 748 individuals from 367 families, the transmission of the MET C allele from parent to child was consistently associated with both social and communication phenotypes of autism. Stratification by gastrointestinal conditions revealed a similar pattern of association with both social and communication phenotypes in 242 individuals with autism from 118 families with co-occurring gastrointestinal conditions, but a lack of association with any domain in 181 individuals from 96 families with ASD and no co-occurring gastrointestinal condition. These data indicate that the MET C allele influences at least two of the three domains of the autism triad.
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Affiliation(s)
- Daniel B. Campbell
- Department of Pharmacology, Vanderbilt University, Nashville, TN,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN
| | - Dana Warren
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN
| | - James S. Sutcliffe
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Evon Batey Lee
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN,Department of Pediatrics, Vanderbilt University, Nashville, TN
| | - Pat Levitt
- Department of Pharmacology, Vanderbilt University, Nashville, TN,Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN
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18
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Cannon DS, Miller JS, Robison RJ, Villalobos ME, Wahmhoff NK, Allen-Brady K, McMahon WM, Coon H. Genome-wide linkage analyses of two repetitive behavior phenotypes in Utah pedigrees with autism spectrum disorders. Mol Autism 2010; 1:3. [PMID: 20678246 PMCID: PMC2907569 DOI: 10.1186/2040-2392-1-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 02/22/2010] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND It has been suggested that efforts to identify genetic risk markers of autism spectrum disorder (ASD) would benefit from the analysis of more narrowly defined ASD phenotypes. Previous research indicates that 'insistence on sameness' (IS) and 'repetitive sensory-motor actions' (RSMA) are two factors within the ASD 'repetitive and stereotyped behavior' domain. The primary aim of this study was to identify genetic risk markers of both factors to allow comparison of those markers with one another and with markers found in the same set of pedigrees using ASD diagnosis as the phenotype. Thus, we empirically addresses the possibilities that more narrowly defined phenotypes improve linkage analysis signals and that different narrowly defined phenotypes are associated with different loci. Secondary aims were to examine the correlates of IS and RSMA and to assess the heritability of both scales. METHODS A genome-wide linkage analysis was conducted with a sample of 70 multiplex ASD pedigrees using IS and RSMA as phenotypes. Genotyping services were provided by the Center for Inherited Disease Research using the 6 K single nucleotide polymorphism linkage panel. Analysis was done using the multipoint linkage software program MCLINK, a Markov chain Monte Carlo (MCMC) method that allows for multilocus linkage analysis on large extended pedigrees. RESULTS Genome-wide significance was observed for IS at 2q37.1-q37.3 (dominant model heterogeneity lod score (hlod) 3.42) and for RSMA at 15q13.1-q14 (recessive model hlod 3.93). We found some linkage signals that overlapped and others that were not observed in our previous linkage analysis of the ASD phenotype in the same pedigrees, and regions varied in the range of phenotypes with which they were linked. A new finding with respect to IS was that it is positively associated with IQ if the IS-RSMA correlation is statistically controlled. CONCLUSIONS The finding that IS and RSMA are linked to different regions that only partially overlap regions previously identified with ASD as the phenotype supports the value of including multiple, narrowly defined phenotypes in ASD genetic research. Further, we replicated previous reports indicating that RSMA is more strongly associated than IS with measures of ASD severity.
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Affiliation(s)
- Dale S Cannon
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - Judith S Miller
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - Reid J Robison
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - Michele E Villalobos
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - Natalie K Wahmhoff
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - Kristina Allen-Brady
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - William M McMahon
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
| | - Hilary Coon
- Utah Autism Research Project, Department of Psychiatry, University of Utah, 650 Komas Drive, Suite 206, Salt Lake City, UT, 84108-3528, USA
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19
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Ronald A, Butcher LM, Docherty S, Davis OSP, Schalkwyk LC, Craig IW, Plomin R. A genome-wide association study of social and non-social autistic-like traits in the general population using pooled DNA, 500 K SNP microarrays and both community and diagnosed autism replication samples. Behav Genet 2009; 40:31-45. [PMID: 20012890 PMCID: PMC2797846 DOI: 10.1007/s10519-009-9308-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 10/14/2009] [Indexed: 10/28/2022]
Abstract
Two separate genome-wide association studies were conducted to identify single nucleotide polymorphisms (SNPs) associated with social and nonsocial autistic-like traits. We predicted that we would find SNPs associated with social and non-social autistic-like traits and that different SNPs would be associated with social and nonsocial. In Stage 1, each study screened for allele frequency differences in approximately 430,000 autosomal SNPs using pooled DNA on microarrays in high-scoring versus low-scoring boys from a general population sample (N = approximately 400/group). In Stage 2, 22 and 20 SNPs in the social and non-social studies, respectively, were tested for QTL association by individually genotyping an independent community sample of 1,400 boys. One SNP (rs11894053) was nominally associated (P < .05, uncorrected for multiple testing) with social autistic-like traits. When the sample was increased by adding females, 2 additional SNPs were nominally significant (P < .05). These 3 SNPs, however, showed no significant association in transmission disequilibrium analyses of diagnosed ASD families.
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Affiliation(s)
- Angelica Ronald
- Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
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20
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Jacob S, Landeros-Weisenberger A, Leckman JF. Autism spectrum and obsessive-compulsive disorders: OC behaviors, phenotypes and genetics. Autism Res 2009; 2:293-311. [PMID: 20029829 PMCID: PMC3974607 DOI: 10.1002/aur.108] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Autism spectrum disorders (ASDs) are a phenotypically and etiologically heterogeneous set of disorders that include obsessive-compulsive behaviors (OCB) that partially overlap with symptoms associated with obsessive-compulsive disorder (OCD). The OCB seen in ASD vary depending on the individual's mental and chronological age as well as the etiology of their ASD. Although progress has been made in the measurement of the OCB associated with ASD, more work is needed including the potential identification of heritable endophenotypes. Likewise, important progress toward the understanding of genetic influences in ASD has been made by greater refinement of relevant phenotypes using a broad range of study designs, including twin and family-genetic studies, parametric and nonparametric linkage analyses, as well as candidate gene studies and the study of rare genetic variants. These genetic analyses could lead to the refinement of the OCB phenotypes as larger samples are studied and specific associations are replicated. Like ASD, OCB are likely to prove to be multidimensional and polygenic. Some of the vulnerability genes may prove to be generalist genes influencing the phenotypic expression of both ASD and OCD while others will be specific to subcomponents of the ASD phenotype. In order to discover molecular and genetic mechanisms, collaborative approaches need to generate shared samples, resources, novel genomic technologies, as well as more refined phenotypes and innovative statistical approaches. There is a growing need to identify the range of molecular pathways involved in OCB related to ASD in order to develop novel treatment interventions.
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Affiliation(s)
- Suma Jacob
- Department of Psychiatry, University of Illinois School, Chicago, Illinois 60612, USA.
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21
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Veenstra-VanderWeele J, Jessen TN, Thompson BJ, Carter M, Prasad HC, Steiner JA, Sutcliffe JS, Blakely RD. Modeling rare gene variation to gain insight into the oldest biomarker in autism: construction of the serotonin transporter Gly56Ala knock-in mouse. J Neurodev Disord 2009; 1:158-71. [PMID: 19960097 PMCID: PMC2786076 DOI: 10.1007/s11689-009-9020-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/25/2009] [Indexed: 12/16/2022] Open
Abstract
Alterations in peripheral and central indices of serotonin (5-hydroxytryptamine, 5-HT) production, storage and signaling have long been associated with autism. The 5-HT transporter gene (HTT, SERT, SLC6A4) has received considerable attention as a potential risk locus for autism-spectrum disorders, as well as disorders with overlapping symptoms, including obsessive-compulsive disorder (OCD). Here, we review our efforts to characterize rare, nonsynonymous polymorphisms in SERT derived from multiplex pedigrees carrying diagnoses of autism and OCD and present the initial stages of our effort to model one of these variants, Gly56Ala, in vivo. We generated a targeting vector to produce the Gly56Ala substitution in the Slc6a4 locus by homologous recombination. Following removal of a neomycin resistance selection cassette, animals exhibiting germline transmission of the Ala56 variant were bred to establish a breeding colony on a 129S6 background, suitable for initial evaluation of biochemical, physiological and behavioral alterations relative to SERT Gly56 (wild-type) animals. SERT Ala56 mice were achieved and exhibit a normal pattern of transmission. The initial growth and gross morphology of these animals is comparable to wildtype littermate controls. The SERT Ala56 variant can be propagated in 129S6 mice without apparent disruption of fertility and growth. We discuss both the opportunities and challenges that await the physiological/behavioral analysis of Gly56Ala transgenic mice, with particular reference to modeling autism-associated traits.
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Affiliation(s)
- Jeremy Veenstra-VanderWeele
- Departments of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - Tammy N. Jessen
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - Brent J. Thompson
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - Michelle Carter
- Departments of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - Harish C. Prasad
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - Jennifer A. Steiner
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - James. S. Sutcliffe
- Departments of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
| | - Randy D. Blakely
- Departments of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232-8548 USA
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22
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Influence of the 5-HTTLPR polymorphism and environmental risk factors in a Brazilian sample of patients with autism spectrum disorders. Brain Res 2009; 1267:9-17. [DOI: 10.1016/j.brainres.2009.02.072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 02/21/2009] [Accepted: 02/28/2009] [Indexed: 11/19/2022]
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23
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Guhathakurta S, Sinha S, Ghosh S, Chatterjee A, Ahmed S, Gangopadhyay PK, Usha R. Population-based association study and contrasting linkage disequilibrium pattern reveal genetic association of SLC6A4 with autism in the Indian population from West Bengal. Brain Res 2008; 1240:12-21. [DOI: 10.1016/j.brainres.2008.08.063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 06/23/2008] [Accepted: 08/24/2008] [Indexed: 12/11/2022]
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24
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The 'fractionable autism triad': a review of evidence from behavioural, genetic, cognitive and neural research. Neuropsychol Rev 2008; 18:287-304. [PMID: 18956240 DOI: 10.1007/s11065-008-9076-8] [Citation(s) in RCA: 282] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 09/13/2008] [Indexed: 10/21/2022]
Abstract
Autism is diagnosed on the basis of a triad of impairments in social interaction, communication, and flexible imaginative functions (with restricted and repetitive behaviors and interests; RRBIs). There has been a strong presumption that these different features of the syndrome are strongly intertwined and proceed from a common cause at the genetic, cognitive and neural levels. In this review we examine evidence for an alternative approach, considering the triad as largely 'fractionable'. We present evidence from our own twin studies, and review relevant literature on autism and autistic-like traits in other groups. We suggest that largely independent genes may operate on social skills/impairments, communication abilities, and RRBIs, requiring a change in molecular-genetic research approaches. At the cognitive level, we suggest that satisfactory accounts exist for each of the triad domains, but no single unitary account can explain both social and nonsocial features of autism. We discuss the implications of the fractionable-triad approach for both diagnosis and future research directions.
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25
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Huang CH, Santangelo SL. Autism and serotonin transporter gene polymorphisms: a systematic review and meta-analysis. Am J Med Genet B Neuropsychiatr Genet 2008; 147B:903-13. [PMID: 18286633 DOI: 10.1002/ajmg.b.30720] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The serotonin transporter gene (5-HTT) plays a crucial role in serotonergic neurotransmission and has been found to be associated, with varying degrees of significance, with many diseases, including autism. Prior association studies of autism have yielded conflicting results regarding the association between two common 5-HTT polymorphisms, the promoter insertion/deletion (5-HTTLPR) and the intron 2 VNTR (STin2 VNTR). We conducted a systematic review and meta-analysis to test the following hypotheses: (i) there is an association between autism and either or both of the 5-HTTLPR and STin2 VNTR polymorphisms, and (ii) the S allele of 5-HTTLPR and/or the STin2.12 allele of the VNTR are the specific risk alleles for autism. All published family-based and population based studies were examined to determine the overall strength of association between 5-HTT polymorphisms and autism. After exclusion of studies with overlapping samples and studies whose data did not allow for calculation of an odds ratio, 16 studies were included for final analyses, all but two of which used a family-based design. The meta-analysis failed to find a significant overall association between either of the 5-HTT polymorphisms examined and autism. Further, no allelic transmission distortion was found when studies of simplex (11 studies) and multiplex (3 studies) family samples were analyzed separately. However, there was significant heterogeneity by ethnicity; family based studies of US mixed population samples showed preferential transmission of the S allele of 5-HTTLPR (S allele:L allele = 247:183), while there was no allelic distortion among the family-based studies of European and Asian samples.
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Affiliation(s)
- Christine H Huang
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
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26
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Losh M, Sullivan PF, Trembath D, Piven J. Current developments in the genetics of autism: from phenome to genome. J Neuropathol Exp Neurol 2008; 67:829-37. [PMID: 18716561 PMCID: PMC2649757 DOI: 10.1097/nen.0b013e318184482d] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Despite compelling evidence from twin and family studies indicating a strong genetic involvement in the etiology of autism, the unequivocal detection of autism susceptibility genes remains an elusive goal. The purpose of this review is to evaluate the current state of autism genetics research, with attention focused on new techniques and analytic approaches. We first present a brief overview of evidence for the genetic basis of autism, followed by an appraisal of linkage and candidate gene study findings and consideration of new analytic approaches to the study of complex psychiatric conditions, namely, genome-wide association studies, assessment of structural variation within the genome, and the incorporation of endophenotypes in genetic analysis.
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Affiliation(s)
- Molly Losh
- Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7190, USA.
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27
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Herrick KA, Rossen LM, Nielsen SJ, Branum AM, Ogden CL. Macrophage migration inhibitory factor and autism spectrum disorders. Pediatrics 2008. [PMID: 26391940 DOI: 10.1542/peds] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVE Autistic spectrum disorders are childhood neurodevelopmental disorders characterized by social and communicative impairment and repetitive and stereotypical behavior. Macrophage migration inhibitory factor (MIF) is an upstream regulator of innate immunity that promotes monocyte/macrophage-activation responses by increasing the expression of Toll-like receptors and inhibiting activation-induced apoptosis. On the basis of results of previous genetic linkage studies and reported altered innate immune response in autism spectrum disorder, we hypothesized that MIF could represent a candidate gene for autism spectrum disorder or its diagnostic components. METHODS Genetic association between autism spectrum disorder and MIF was investigated in 2 independent sets of families of probands with autism spectrum disorder, from the United States (527 participants from 152 families) and Holland (532 participants from 183 families). Probands and their siblings, when available, were evaluated with clinical instruments used for autism spectrum disorder diagnoses. Genotyping was performed for 2 polymorphisms in the promoter region of the MIF gene in both samples sequentially. In addition, MIF plasma analyses were conducted in a subset of Dutch patients from whom plasma was available. RESULTS There were genetic associations between known functional polymorphisms in the promoter for MIF and autism spectrum disorder-related behaviors. Also, probands with autism spectrum disorder exhibited higher circulating MIF levels than did their unaffected siblings, and plasma MIF concentrations correlated with the severity of multiple autism spectrum disorder symptoms. CONCLUSIONS These results identify MIF as a possible susceptibility gene for autism spectrum disorder. Additional research is warranted on the precise relationship between MIF and the behavioral components of autism spectrum disorder, the mechanism by which MIF contributes to autism spectrum disorder pathogenesis, and the clinical use of MIF genotyping.
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Affiliation(s)
| | - Lauren M Rossen
- Infant, Child, and Women's Health Statistics Branch, Office of Analysis and Epidemiology, and
| | | | - Amy M Branum
- Reproductive Statistics Branch, Division of Vital Statistics, National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland
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28
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Grigorenko EL, Han SS, Yrigollen CM, Leng L, McDonald C, Mizue Y, Anderson GM, Mulder EJ, de Bildt A, Minderaa RB, Volkmar FR, Chang JT, Bucala R. Macrophage migration inhibitory factor and autism spectrum disorders. Pediatrics 2008; 122:e438-45. [PMID: 18676531 PMCID: PMC3816765 DOI: 10.1542/peds.2007-3604] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE Autistic spectrum disorders are childhood neurodevelopmental disorders characterized by social and communicative impairment and repetitive and stereotypical behavior. Macrophage migration inhibitory factor (MIF) is an upstream regulator of innate immunity that promotes monocyte/macrophage-activation responses by increasing the expression of Toll-like receptors and inhibiting activation-induced apoptosis. On the basis of results of previous genetic linkage studies and reported altered innate immune response in autism spectrum disorder, we hypothesized that MIF could represent a candidate gene for autism spectrum disorder or its diagnostic components. METHODS Genetic association between autism spectrum disorder and MIF was investigated in 2 independent sets of families of probands with autism spectrum disorder, from the United States (527 participants from 152 families) and Holland (532 participants from 183 families). Probands and their siblings, when available, were evaluated with clinical instruments used for autism spectrum disorder diagnoses. Genotyping was performed for 2 polymorphisms in the promoter region of the MIF gene in both samples sequentially. In addition, MIF plasma analyses were conducted in a subset of Dutch patients from whom plasma was available. RESULTS There were genetic associations between known functional polymorphisms in the promoter for MIF and autism spectrum disorder-related behaviors. Also, probands with autism spectrum disorder exhibited higher circulating MIF levels than did their unaffected siblings, and plasma MIF concentrations correlated with the severity of multiple autism spectrum disorder symptoms. CONCLUSIONS These results identify MIF as a possible susceptibility gene for autism spectrum disorder. Additional research is warranted on the precise relationship between MIF and the behavioral components of autism spectrum disorder, the mechanism by which MIF contributes to autism spectrum disorder pathogenesis, and the clinical use of MIF genotyping.
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Affiliation(s)
- Elena L. Grigorenko
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT 06519, USA,Department of Psychology, Yale University, 2 Hillhouse Ave, New Haven, CT 06520, USA,Department of Epidemiology and Public Health, Yale University, 300 Cedar St, New Haven, CT 06520,Department of Psychology, Moscow State University, 11/5 Mokhovaia St, Moscow 125009, Russia,To whom correspondence should be addressed: Telephone: 203-737-1453, 203-737-2316, Fax: 203-785-7053, 203-785-3002, ,
| | - Summer S. Han
- Department of Psychology, Moscow State University, 11/5 Mokhovaia St, Moscow 125009, Russia
| | - Carolyn M. Yrigollen
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT 06519, USA
| | - Lin Leng
- Department of Epidemiology and Public Health, Yale University, 300 Cedar St, New Haven, CT 06520,Departments of Internal Medicine and Pathology, Yale University, 300 Cedar St, New Haven, CT 06520
| | - Courtney McDonald
- Department of Epidemiology and Public Health, Yale University, 300 Cedar St, New Haven, CT 06520,Departments of Internal Medicine and Pathology, Yale University, 300 Cedar St, New Haven, CT 06520
| | - Yuka Mizue
- Sapporo Immuno Diagnostic Laboratory, 12-20, Shinkawa 2-2, Kita-ku, Sapporo 001-0922, Japan
| | - George M. Anderson
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT 06519, USA
| | - Erik J. Mulder
- Accare/University Medical Center Groningen, University Center for Child and Adolescent Psychiatry, P.O. Box 660, 9700 AR Groningen, the Netherlands
| | - Annelies de Bildt
- Accare/University Medical Center Groningen, University Center for Child and Adolescent Psychiatry, P.O. Box 660, 9700 AR Groningen, the Netherlands
| | - Ruud B. Minderaa
- Accare/University Medical Center Groningen, University Center for Child and Adolescent Psychiatry, P.O. Box 660, 9700 AR Groningen, the Netherlands
| | - Fred R. Volkmar
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT 06519, USA,Department of Psychology, Yale University, 2 Hillhouse Ave, New Haven, CT 06520, USA
| | - Joseph T. Chang
- Department of Psychology, Moscow State University, 11/5 Mokhovaia St, Moscow 125009, Russia
| | - Richard Bucala
- Department of Epidemiology and Public Health, Yale University, 300 Cedar St, New Haven, CT 06520,Departments of Internal Medicine and Pathology, Yale University, 300 Cedar St, New Haven, CT 06520,To whom correspondence should be addressed: Telephone: 203-737-1453, 203-737-2316, Fax: 203-785-7053, 203-785-3002, ,
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29
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Abstract
BACKGROUND SERT I425V, an uncommon missense single nucleotide polymorphism producing a gain-of-function of the serotonin transporter (SERT), was originally found to segregate with a primarily obsessive-compulsive disorder (OCD) but complexly comorbid phenotype in two unrelated families. OBJECTIVE As two individuals with SERT I425V and OCD also had Asperger syndrome (AS), an autism spectrum disorder, and as other rare SERT variants have recently shown significant associations with autism, we set out to extend our original OCD study by genotyping additional autism/AS and OCD samples. METHODS Case-control association study of SERT I425V in 210 AS/autism probands and 215 controls, plus 335 OCD probands and their family members. RESULTS SERT I425V was not found in any of the individuals with AS/autism, OCD alone or OCD comorbid with AS and other disorders, or in controls. This results in new estimates of SERT I425V having a 1.5% prevalence in 530 individuals with OCD from five unrelated families genotyped by us and by one other group and a 0.23% frequency in four control populations totaling 1300 individuals, yielding a continuing significant OCD-control difference (Fisher's exact test corrected for family coefficient of identity P=0.004, odds ratio=6.54). CONCLUSION As several other uncommon, less well quantitated genetic variations occur with an OCD phenotype, including chromosomal anomalies and some other rare gene variants (SGCE, GCH1 and SLITRK1), a tentative conclusion is that OCD resembles other complex disorders in being etiologically heterogeneous and in having both highly penetrant familial subtypes associated with rare alleles or chromosomal anomalies, as well as having a more common, polygenetic form that may involve polymorphisms in such genes as BDNF, COMT, GRIN2beta, TPH2, HTR2A and SLC1A1.
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Allan AM, Liang X, Luo Y, Pak C, Li X, Szulwach KE, Chen D, Jin P, Zhao X. The loss of methyl-CpG binding protein 1 leads to autism-like behavioral deficits. Hum Mol Genet 2008; 17:2047-57. [PMID: 18385101 DOI: 10.1093/hmg/ddn102] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Methyl-CpG binding proteins (MBDs) are central components of DNA methylation-mediated epigenetic gene regulation. Alterations of epigenetic pathways are known to be associated with several neurodevelopmental disorders, particularly autism. Our previous studies showed that the loss of Mbd1 led to reduced hippocampal neurogenesis and impaired learning in mice. However, whether MBD1 regulates the autism-related cognitive functions remains unknown. Here we show that Mbd1 mutant (Mbd1(-/-)) mice exhibit several core deficits frequently associated with autism, including reduced social interaction, learning deficits, anxiety, defective sensory motor gating, depression and abnormal brain serotonin activity. Furthermore, we find that Mbd1 can directly regulate the expression of Htr2c, one of the serotonin receptors, by binding to its promoter, and the loss of Mbd1 led to elevated expression of Htr2c. Our results, therefore, demonstrate the importance of epigenetic regulation in mammalian brain development and cognitive functions. Understanding how the loss of Mbd1 could lead to autism-like behavioral phenotypes would reveal much-needed information about the molecular pathogenesis of autism.
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Affiliation(s)
- Andrea M Allan
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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31
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Obstetric and Parental Psychiatric Variables as Potential Predictors of Autism Severity. J Autism Dev Disord 2008; 38:1542-54. [DOI: 10.1007/s10803-007-0536-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 12/28/2007] [Indexed: 10/22/2022]
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Posey DJ, Stigler KA, Erickson CA, McDougle CJ. Antipsychotics in the treatment of autism. J Clin Invest 2008; 118:6-14. [PMID: 18172517 PMCID: PMC2171144 DOI: 10.1172/jci32483] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Atypical antipsychotics have become indispensable in the treatment of a variety of symptoms in autism. They are frequently used to treat irritability and associated behaviors including aggression and self injury. They may also be efficacious for hyperactivity and stereotyped behavior. This review presents the rationale for the use of this drug class in autism and reviews the most important studies published on this topic to date. Significant adverse effects, including weight gain and the possibility of tardive dyskinesia, are reviewed. Future research directions are discussed.
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Affiliation(s)
- David J Posey
- Christian Sarkine Autism Treatment Center, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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34
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Hohmann CF, Walker EM, Boylan CB, Blue ME. Neonatal serotonin depletion alters behavioral responses to spatial change and novelty. Brain Res 2007; 1139:163-77. [PMID: 17296168 PMCID: PMC1974858 DOI: 10.1016/j.brainres.2006.12.095] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 10/19/2006] [Accepted: 12/29/2006] [Indexed: 10/23/2022]
Abstract
Multiple brain disorders that show serotonergic imbalances have a developmental onset. Experimental models indicate a role for serotonin as a morphogen in brain development. To selectively study the effects of serotonin depletions on cortical structural development and subsequent behavior, we developed a mouse model in which a serotonin neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), is injected into the medial forebrain bundle (mfb) on the day of birth. Littermates with saline injections into the mfb and age matched mice served as controls. This study characterized the extent and duration of serotonergic denervation after the selective neonatal lesion and investigated effects on exploratory behavior, spatial learning and anxiety in mice of both sexes. We report significant decreases in the serotonergic (5-HT) innervation to cortex and hippocampus, but not to subcortical forebrain structures in 5,7-DHT-lesioned mice. The depletion of 5-HT fibers in cortical areas was long lasting in lesioned mice but autoradiographic binding to high affinity 5-HT transporters was only transiently reduced. Male but not female lesioned mice reduced their exploration significantly in response to spatial rearrangement and object novelty, suggesting increased anxiety in response to change but normal spatial cognition. Our data show that developmental disruptions in the serotonergic innervation of cortex and hippocampus are sufficient to induce permanent, sex specific, behavioral alterations. These results may have significant implications for understanding brain disorders presenting with cortical morphogenetic abnormalities and altered serotonin neurotransmission, such as autism, schizophrenia and affective disorders.
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Stone JL, Merriman B, Cantor RM, Geschwind DH, Nelson SF. High density SNP association study of a major autism linkage region on chromosome 17. Hum Mol Genet 2007; 16:704-15. [PMID: 17376794 DOI: 10.1093/hmg/ddm015] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A region on chromosome 17 has recently been highlighted as linked to autism (MIM[209850]) in multiple studies and evidence has accumulated suggesting that male-only families (those families that have produced only affected males) provide the major contribution to linkage at this locus. In an attempt to comprehensively test for association of common variants to autism within the region on chromosome 17 defined in Stone et al. (Stone, J.L., Merriman, B., Cantor, R.M., Yonan, A.L., Gilliam, T.C., Geschwind, D.H. and Nelson, S.F. (2004) Evidence for sex-specific risk alleles in autism spectrum disorder. Am. J. Hum. Genet., 75, 1117-1123), a dense panel of single nucleotide polymorphisms (SNPs) was selected across the linkage peak and analyzed in a trio-based study design. SNPs were genotyped in 219 independent trios at an average intermarker distance of 6.1 kb across the 13.7 Mb interval. This provided ~80% coverage of common HapMap variation present in Caucasians, testing exonic, intronic, promoter and intergenic regions, as knowledge of important functional regions within the genome is currently limited. In this comprehensive association study of a linkage region in autism, no single SNP or haplotype association was sufficient to account for the initial linkage signal. Nominally significant single SNP and/or haplotype-based association results were detected in 15 genes, of which, MYO1D, ACCN1 and LASP1 stand out as genes with autism risk alleles requiring further study, with potential GRRs in the range of 1.34-2.29.
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Affiliation(s)
- Jennifer L Stone
- Department of Human Genetics, University of California, Los Angeles, CA 90095, USA
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Cho IH, Yoo HJ, Park M, Lee YS, Kim SA. Family-based association study of 5-HTTLPR and the 5-HT2A receptor gene polymorphisms with autism spectrum disorder in Korean trios. Brain Res 2007; 1139:34-41. [PMID: 17280648 DOI: 10.1016/j.brainres.2007.01.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 12/19/2006] [Accepted: 01/02/2007] [Indexed: 11/25/2022]
Abstract
The potential role of the serotoninergic system in the development of autistic disorder has long been suggested based on the observation of hyperserotoninemia in autistic subjects and the results of drug treatment studies. Promoter region polymorphisms (5-HTTLPR) of the serotonin transporter gene (SLC6A4) and the 5-HT2A receptor gene (HTR2A) have been studied as potential candidate genes in autism spectrum disorder (ASD). The objective of this family-based linkage/association study is to evaluate the relationship between ASD and 5-HTTLPR as well as that between some SNPs of HTR2A and ASD in Korean trios by using the transmission disequilibrium test (TDT). Genotyping was performed for 5-HTTLPR and two single nucleotide polymorphisms (SNPs) (-1438G/A and 102T/C) of HTR2A. The TDT, linkage disequilibrium (LD) analysis and haplotype analysis were performed. This study comprised 126 complete trios of ASD patients and both parents. With regard to the transmission of 5-HTTLPR, the long allelic variant was preferentially transmitted in the ASD subjects. Based on the TDT results, there was no significant difference in the transmission of the two SNPs of HTR2A. However, in the results of the haplotype analysis, the AT haplotype demonstrated significant evidence of association with autism. The global chi(2) test for haplotype transmission revealed a significant association between HTR2A and autism. Although we identified a significant association between ASD and 5-HTTLPR as well as between ASD and HTR2A, it cannot exclude the chance finding because of the low level of statistical significance and relatively small power. We believe that further studies are required to examine the relationship between serotonin-related genes and the behavioral phenotypes of ASD in the Korean population.
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Affiliation(s)
- In Hee Cho
- Department of Psychiatry, Gachon University of Medicine and Science, 1198 Guwol-Dong, Namdong-Gu, Incheon, 405-760, Republic of Korea
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Hus V, Pickles A, Cook EH, Risi S, Lord C. Using the autism diagnostic interview--revised to increase phenotypic homogeneity in genetic studies of autism. Biol Psychiatry 2007; 61:438-48. [PMID: 17276746 DOI: 10.1016/j.biopsych.2006.08.044] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 07/26/2006] [Accepted: 08/21/2006] [Indexed: 01/06/2023]
Abstract
BACKGROUND Many chromosomal regions for susceptibility to autism spectrum disorders (ASDs) have been identified, but few have reached genomewide significance. In response, researchers have attempted to increase the power of their analyses by stratifying samples to increase phenotypic homogeneity. Although homogeneity has typically been defined by a single variable, resultant groups often differ in other dimensions that may be directly pertinent. Group differences in age, gender, IQ, and measures of autism severity are examined as related to Autism Diagnostic Interview-Revised (ADI-R) domains previously used for subsetting or Quantitative Trait Analysis (QTL). METHODS Participants were research participants and clinic referrals for assessment of possible autism. Assessments included the ADI-R, Autism Diagnostic Observation Schedule, Vineland Adaptive Behavior Scales, and a developmental or cognitive test. Data were collected for 983 individuals, ages 4 to 52 years, with diagnoses of autism and ASDs. RESULTS Findings suggest that, of several potential grouping variables, only restricted and repetitive behaviors associated with Insistence on Sameness were independent of age, IQ, and autism severity. CONCLUSIONS Results emphasize the potential unintended effects of stratification and the importance of understanding such interrelationships between phenotypic characteristics when defining subgroups or performing QTL.
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Affiliation(s)
- Vanessa Hus
- University of Michigan Autism and Communication Disorders Center, Ann Arbor, Michigan, USA
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38
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Abstract
Twin and family studies in autistic disorders (AD) have elucidated a high heritability of the narrow and broad phenotype of AD. In this review on the genetics of AD, we will initially delineate the phenotype of AD and discuss aspects of differential diagnosis, which are particularly relevant with regard to the genetics of autism. Cytogenetic and molecular genetic studies will be presented in detail, and the possibly involved aetiopathological pathways will be described. Implications of the different genetic findings for genetic counselling will be mentioned.
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Affiliation(s)
- C M Freitag
- Department of Child and Adolescent Psychiatry, Saarland University Hospital, Homburg, Germany.
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Anxiety- and novelty seeking-related personality traits and serotonin transporter gene polymorphisms. J Psychiatr Res 2006; 40:568-76. [PMID: 16313923 DOI: 10.1016/j.jpsychires.2005.10.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 09/28/2005] [Accepted: 10/19/2005] [Indexed: 11/20/2022]
Abstract
The affection of human personality by the promoter and the intron 2 polymorphism in the serotonin transporter gene (SERT) is inconsistently reported. We aimed to clarify this situation by gender-specific haplotype-phenotype association. 98 women and 97 men completed the personality inventories NEO-PI-R and TPQ. The subjects were genotyped for the two SERT polymorphisms and the haplotypes were calculated. The short (S) and long (L) promoter alleles and the 12 and 10 repeat intron 2 alleles formed the haplotypes S 12, S 10, L 12 and L 10. In men, scores in the anxiety-related dimensions were higher in S 12 than in L 12 carriers. Opposite in direction, scores tended to be lower in S 10 than in L 10 carriers. In the novelty seeking-related dimensions, scores were higher in S 10 than in S 12 carriers. No association was observed in women. In conclusion, anxiety- and novelty seeking-related personality dimensions are differentially associated with different SERT haplotypes; the consistent restriction to men suggests common androgen regulation. Opposite trends with haplotypes including the same promoter alleles suggest contribution of group stratification to earlier inconsistent findings and call to further differentiate the molecular function and clinical implications of the SERT promoter polymorphism.
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40
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Ramoz N, Reichert JG, Corwin TE, Smith CJ, Silverman JM, Hollander E, Buxbaum JD. Lack of evidence for association of the serotonin transporter gene SLC6A4 with autism. Biol Psychiatry 2006; 60:186-91. [PMID: 16616719 DOI: 10.1016/j.biopsych.2006.01.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 09/27/2005] [Accepted: 01/09/2006] [Indexed: 11/17/2022]
Abstract
BACKGROUND The serotonin transporter (5-HTT) has long been considered likely to play a role in autism. Hyperserotonemia has been consistently found in a proportion of autistic patients, and the use of selective serotonin reuptake inhibitors (SSRIs) can have a positive effect in treating some symptoms of autism. Specific variants of the 5-HTT gene, SLC6A4, especially the insertion-deletion 5-HTTLPR promoter locus, have been found to modulate its expression and transporter function. METHODS We examined the transmission of the short or long allele of 5-HTTLPR locus to affected individuals, using a large cohort of 352 families. In addition, we screened five single nucleotide polymorphisms (SNPs) in the 5' region of SLC6A4 previously reported to be positively associated with autism, as well as 4 additional SNPs also in the 5' region. RESULTS No association of the 5-HTTLPR locus with autism was found. Furthermore, no evidence for association of any of the nine SNPs covering the SLC6A4 gene, or any of their haplotypes, was observed in our study. Using obsessive-compulsive behaviors (OCB), severe OCBs or rigid-compulsive subsets of our cohort gave the same negative results. CONCLUSIONS SLC6A4 variants do not appear to be significantly involved in the liability to autism.
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Affiliation(s)
- Nicolas Ramoz
- Laboratory of Molecular Neuropsychiatry, Department of Psychiatry, Seaver Autism Research Center, Mount Sinai School of Medicine, New York, New York 10029, USA
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Koishi S, Yamamoto K, Matsumoto H, Koishi S, Enseki Y, Oya A, Asakura A, Aoki Y, Atsumi M, Iga T, Inomata J, Inoko H, Sasaki T, Nanba E, Kato N, Ishii T, Yamazaki K. Serotonin transporter gene promoter polymorphism and autism: a family-based genetic association study in Japanese population. Brain Dev 2006; 28:257-60. [PMID: 16481140 DOI: 10.1016/j.braindev.2005.09.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Revised: 08/24/2005] [Accepted: 09/05/2005] [Indexed: 11/22/2022]
Abstract
Autism is now widely accepted as a biological disorder which, by and large, starts before birth. It has been shown that serotonin (5-HT) is associated with several psychological processes and hyperserotoninemia is observed in some autistic patients. The results of previous reports about family-based association studies between the serotonin transporter (5-HTT) gene promoter polymorphism and autism are controversial. In this study, an analysis using the transmission/disequilibrium test (TDT) between the 5-HTT gene promoter polymorphism and autism in 104 trios, all ethnically Japanese, showed no significant linkage disequilibrium (P=0.17). Recently, it has been reported that some haplotypes at the serotonin transporter locus may be associated with the pathogenesis of autism. Therefore, further investigations by haplotype analyses are necessary to confirm the implications of genetic variants of the serotonin transporter in the etiology of autism.
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Affiliation(s)
- Shinko Koishi
- Department of Psychiatry, Course of Specialized Clinical Science, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan
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Bacchelli E, Maestrini E. Autism spectrum disorders: Molecular genetic advances. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2006; 142C:13-23. [PMID: 16419096 DOI: 10.1002/ajmg.c.30078] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Despite the strong genetic basis of autism spectrum disorders (ASD), research efforts in the last decade have not been successful in the identification of confirmed susceptibility genes. We review the present status of genetic linkage, candidate gene, and association studies, pointing out the limitations of these approaches and the challenge of dealing with the clinical and genetic complexity of autism. Finally, we outline how recent technological and bioinformatic advances, together with an increasing understanding of the structure of the human genome, have set the stage to perform more comprehensive and well powered studies, possibly leading to a turning point in the understanding of the genetic basis of this devastating disorder.
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Affiliation(s)
- Elena Bacchelli
- Dipartimento di Biologia Evoluzionistica Sperimentale, Bologna University, via Selmi 3, 40126 Bologna, Italy
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Qiu S, Korwek KM, Weeber EJ. A fresh look at an ancient receptor family: emerging roles for low density lipoprotein receptors in synaptic plasticity and memory formation. Neurobiol Learn Mem 2005; 85:16-29. [PMID: 16198608 DOI: 10.1016/j.nlm.2005.08.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 07/30/2005] [Accepted: 08/11/2005] [Indexed: 01/11/2023]
Abstract
The well-known family of low-density lipoprotein receptors represents a collection of ancient membrane receptors that have been remarkably conserved throughout evolution. These multifunctional receptors, known to regulate cholesterol transport, are becoming increasingly interesting to the neuroscience community due to their ability to transduce a diversity of extracellular signals across the membrane in the adult CNS. Their roles in modulating synaptic plasticity and necessity in hippocampus-specific learning and memory have recently come to light. In addition, genetic, biochemical and behavioral studies have implicated these signaling systems in a number of human neurodegenerative and neuropsychiatric disorders involving loss of cognitive ability, such as Alzheimer's disease, schizophrenia and autism. This review describes the known functions of these receptors and discusses their potential role in processes of synaptic regulation and memory formation.
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Affiliation(s)
- Shenfeng Qiu
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0615, USA
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